Coated steel pipe, also known as coated pipe, steel plastic composite pipe, or coated composite steel pipe, is a steel plastic composite steel pipe that uses a steel pipe as the substrate and fuses a plastic anti-corrosion layer on the inner surface of the steel pipe (bottom pipe) or on the inner and outer surfaces through spraying, rolling, immersion, and suction processes. Coated steel pipes have excellent corrosion resistance and relatively low friction resistance. Epoxy resin coated steel pipes are suitable for transporting media such as water supply and drainage, seawater, warm water, oil, and gas, while polyvinyl chloride coated steel pipes are suitable for transporting media such as drainage, seawater, oil, and gas